Round tenons have been long and widely used in woodworking, particularly in furniture making, and most particularly in chair making. Such tenons are used for attachment of chair rungs to chair legs and for securing other furniture and chair parts. Round tenons may be provided by securing a short length of round dowel in a suitably shaped and placed hole on the part requiring a tenon. More typically however, a round tenon is formed on the part itself, which part may also be round or have a square, rectangular or differently shaped cross section.
Many tenons, particularly in chair parts, have a truncated conical shape, i.e. are round but tapered. Such tenons are desirable in that they provide a snug fit in an appropriately shaped mortise (that is tapered). However, slight relative movement between the joint members loosens the joint. By contrast, accurately sized cylindrical tenons can move in a mortise without loosening. Furthermore, the mortise-containing furniture member can lock around a cylindrical the tenon as the mortise member dries and shrinks.
A substantial number of methods and devices have been used for forming such tenons. They may be formed by hand using a pocket knife, draw knife, chisel, spoke shave or other tools. They may be formed on general purpose equipment like lathes and drill presses, and in some instances they may be formed using dedicated machines like the Stanley number 77 dowel making machine (although this machine will accept only a limited range of sizes of work pieces). There are also a variety of tenon forming cutters intended to be rotated against a work piece utilizing a brace. Finally, high speed tenon-forming cutters for use in a drill press are available.
Some such devices are intended to form tenons having only a particular diameter or group of predetermined diameters. Others are purportedly capable of producing a range of tenon diameters. Most of these devices, including for the Stanley number 77 dowel making machine, have a cutting blade or blades that are difficult to sharpen because, among other reasons, their shape is complex.
Drawbacks are associated with all of these devices. Some are large, unwieldy and expensive. All make it difficult or impossible to adjust by small amounts the diameter of the tenon produced. However, the availability of such adjustment is important in order to accommodate the variety of conditions, species, relative moisture contents and other factors presented by various tenon-forming situations. For instance, fiber spring-back may cause tenons formed in green wood to be oversize. Most of these prior tenon-forming techniques and devices also cannot form off-axis tenons and leave an unattractive shoulder on the work piece adjacent to the tenon.
In the face of all these considerations, there has been a recent resurgence of interest in rustic furniture, such as furniture built from "twigs" or other sections of trunks, stems, or branches from which the bark may or may not have been removed, but which retain some of their natural surface shape and character. The continuing need for cylindrical tenons described above, and this resurgence in the popularity of rustic furniture, have created the need for an economical but improved tenon-forming tool.
It is thus an object of this invention to provide a tenon cutter for forming attractive, accurately sized cylindrical tenons with attractive tenon shoulders on components of rustic and other furniture.
It is also an object of this invention to provide tenon cutters that can be operated with hand tools such as braces and, alternatively, with power hand drill motors.
It is another object of this invention to provide tenon cutters that can be adjusted easily and accurately to vary the diameter of tenons produced by small amounts in order to accommodate the need for such variations as a result of the size of mortise that is to receive the tenon, and because of the moisture content or other properties of he wood being used.
It if a further object of the present invention to provide a tenon cutter that uses a blade that may be easily and quickly without significant risk of altering the desired blade profile and with minimal sharpening skill.
Another object of the present invention is facilitation of formation tenons that are accurately aligned with the work piece on which they are formed and, alternatively, of tenons that are off-axis when those are desired.
Yet another object of the present invention is the provision of a tenon cutter design that can be manufactured with sufficient economy to enable retail sale of the tenon cutter, or of a set of tenon cutters in different diameters, at an attractively low price.